I just finished writing the blog post that will show up early in March. The one this week will introduce Haros and Vin, the latest two characters for Amber In that one instead I'll explain a bit what I'll do in future regarding RPGs and games (in practice will slow-down a bit, wait to read the blog though).

Anyway, back to the point of this thread: you know those RPGs where you improve the skills as you use them? the first one was Dungeon Master, where you could improve the skills of any character if you kept using them.
So I was thinking about it, and about the possibility to use that system also in one of my future RPGs. But it's not all, what if you got a big increase for critical fails?
Imagine a game like Planet Stronghold with all those skills. Maybe I would still allow on level up to increase them a bit, but the main way it should be to improve the skill within the game.
If you kept using pistols, your pistol skill would go up, etc. Skill would improve with usage normally.
Then, depending on the battle system, if there could be "critical failures" (beside critical hits), what if you improved the skill by 2 points?
Or even in the non-battle events, like opening a door with lockipcking skills.
The idea is that you learn as you practice, but like in real life, you learn mainly by your mistakes.

I would either have no fixed Classes, or have skill caps based on the Class (for example a Psionic could have Psionic skill up to 500, while other classes could have lower skill cap).

Would seem too weird? I thought it was a nice way to balance a game with a hit or miss system (like XCOM). So yes, you get to miss a target and you're grumpy, but at same time, the skill involved increases by a good amount, so it means that in future it's less likely to happen

Have to find the right balance so there aren't weird incentives. Skyrim does something similar (minus the failure part). May be okay for the weapon skills (at the risk of requiring grinding depending on tuning), but for stuff like lockpicking there often aren't nearly enough opportunities to use them. I think the secondary skills came in handy only three or four times during PS1 for example, so there aren't many opportunities to level up before a key skill check.

Also, given the nature of your rpgs, it may make sense to have the secondary skills (lockpicking, etc.) have a lower skill max than the weapon skills (which you use all the time).

Yes good point, non-combat skills should have a much lower value/range. For PS2 Anima had a better idea though, instead of random chance (which would lead to save-scumming) the non-combat checks would have like a counter with fixed sucess rate. Like you had 1 lockpick skill available, then your choice was when to decide to use it during that chapter/part of the story. Probably a better system.
For the combat skills instead the system above could work well I think.

Could improvement be split between training and practice? Training would allow you to increase low-level skills reliably, but would get slower as your skill increased; practice would depend on moments of 'specialness', critical hits and critical misses, and would increase the same amount regardless of the character's skill. That would mean there'd have to be a system for downtime, and it would help if there was some decay in skills that weren't ever used to encourage people not to waste the time to train everything.

Honestly, I'd rather just assign the skill points at level up. The problem with Skyrim and Oblivion is some conditions required to level a skill are unbalanced. Weapon skills go up easily enough since most players are going to use them to get past the many enemies thrown their way. Armor skills, on the other hand, required the player to take damage, in spite of the natural inclination to avoid damage. In the end, it encouraged odd tactics to grind specific skills.

Haha I forgot about that. I guess depends how the skills are designed.
For example instead of gaining light amor proficiency if you are hit while wearing it, you could gain it automatically based on the amount of turns/time you wear it. Or even based on damage done, not just received, since it could mean you're getting used to fight with that kind of armor.
So I think depends how it's actually implemented.

Resurrecting this thread because recently, since I couldn't get much work done because of heat, I spent some time playing The Elder Scrolls Online. It uses a similar system, though when you level up you also automatically gain skill points in various skills. Also in that game is very difficult to not get it (regarding armor skills)
It's a nice system overall, also the various skilltrees unlocking some active and passive skills. It's nice that you aren't limited at all by a "Class", but if you want you can have a sorcerer using dual wield or other crazy experiments.
Problem is that such system works well for single player RPG, but not sure how it would be in a party... well, I could try something like that maybe in the future Dingirra game since you play "alone" anyway.

I haven't played that one
But did you play Elder Scrolls Online? It's a sort of a mix, I mean on each level up you still have skills to assign, but the various "skill tree" (not sure how to call them) also need to be improved over time.
It's like each skilltree has it's own XP bar, depending how much you use it, with fixed bumps each level up. It's quite interesting since doesn't put fixed roles like does a Class system. But as I said probably would work well mostly with a single player RPG...